Bradley Manning, the former military intelligence analyst who gave classified information to the anti-secrecy site WikiLeaks in 2010, was acquitted of aiding the enemy, the gravest charge laid against him by the US government. He was, however, found guilty of 19 other charges including espionage, theft and computer fraud.

Delivered by Judge Denise Lind at the Fort Meade base, the acquittal on the aiding the enemy charge was a large if somewhat symbolic victory for the defence and to Manning supporters worldwide. All the other guilty verdicts - including six on charges of espionage - still mean that Manning faces spending the rest of his life in prison.

The mixed emotions of the day for supporters of Manning were reflected in a statement from his family. “While we are obviously disappointed in today’s verdicts, we are happy that Judge Lind agreed with us that Brad never intended to help America’s enemies in any way. Brad loves his country and was proud to wear its uniform.”

Following the verdict, WikiLeaks founder Julian Assange accused President Barack Obama of "national security extremism," referring to Manning "the most important journalistic source the world has ever seen".

"The government kept Bradley Manning in a cage, stripped him naked and isolated him in order to break him, an act formally condemned by the United Nations Special Rapporteur for torture. This was never a fair trial," Assange said from inside the Ecuadorean Embassy in London, his home for more than a year.

Assange said WikiLeaks and Manning's own legal team would not rest until the judgement was overturned.

"It is a dangerous precedent and an example of national security extremism. It is a short-sighted judgment that cannot be tolerated and it must be reversed."

After eight weeks of arguments and testimony, the reading of the verdicts took barely five minutes. Once Judge Lind had uttered the not-guilty verdict to the aiding the enemy charge, she delivered a rapid fusillade of mostly guilty verdicts on the other charges, each time glancing over her glasses at Manning. The sentencing phase will begin here tomorrow morning and could last several weeks with both sides expected to bring forward numerous witnesses.

For his part, Manning stood to attention appearing stoic and showing no visible emotion as Judge Lind spoke. Only when the verdicts were over did he briefly talk with his legal team, led by David Coombs, before court was dismissed. While several of his supporters were in the public gallery they also remained quiet.

A military legal source said that notwithstanding the not guilty verdict on aiding the enemy, Manning still faces sentences of up to 136 years for the combined guilty verdicts. However, there are no minimum sentences which means Judge Lind has leeway for leniency. Sentencing may not come until near the end of August, officials said.

“We won the battle, now we need to go win the war,” the lead defence lawyer Mr Coombs said of the sentencing phase after the verdicts were read. “Today is a good day, but Bradley is by no means out of the fire.”

Press freedom advocates had warned that a guilty verdict on aiding the enemy could have cast a chill on journalists trying to hold governments to account and on would-be whistle-blowers. But there was still widespread dismay among civil liberties groups over the full array of the other guilty verdicts.

“It’s hard not to draw the conclusion that Manning's trial was about sending a message: the US government will come after you,” Amnesty International noted. WikiLeaks said the espionage convictions showed “dangerous national security extremism from the Obama administration”.

Even before the trial started on 3 June, Pfc Manning had acknowledged being the source who supplied WikiLeaks, setting in train the largest leak of classified information in US history. In May he pleaded guilty to portions of ten of the 21 charges against him, opening himself up to possibly of 20 years of confinement. Prosecutors decided to press forward nonetheless and seek guilty verdicts on the full versions of all the charges including aiding the enemy.

Judge Lind had deliberated for 16 hours. It was Manning’s own decision to put his fate in her hands only rather than opting for a jury. In closing arguments, the government argued he had betrayed the trust of his country and must have known that the leaked secrets would reach America’s enemies, including al-Qa’ida.

The defence team, however, contended that Manning, who was deployed to Baghdad as an analyst in late 2009, may have been naïve but was good-intentioned in his actions. Making a statement in May alongside his guilty pleas, Manning said he wanted to reveal the “bloodlust” of the US military and so-called disregard for human life.

He transmitted his first batch of papers to WikiLeaks, founded by Assange, on 3 February 2001 with an attached note. “This is possibly one of the more significant documents of our time, removing the fog of war, and revealing the true nature of the 21st century asymmetric warfare. Have a good day.” Thereafter he handed over more than 700,000 documents, including battlefield notes from Iraq and Afghanistan and a video of a US helicopter attack in Baghdad that killed eleven people, including a Reuters photographer and his driver.

In his closing arguments last week, Major Ashden Fein, a military prosecutor, said Manning had stolen the information and “decided to release it to a bunch of anti-government activists and anarchists to achieve maximum exposure, the maximum exposure, and advance his personal quest for notoriety.”

The trial has been slightly eclipsed by Edward Snowden, the contractor for the National Security Agency, who unveiled details of its programmes to trawl private telephone and internet traffic. However, the two cases are hardly unrelated and it may have been the treatment of Manning that persuaded Mr Snowden to flee abroad.

By mid-morning a few dozen pro-Manning protesters had gathered at the gates to the Fort Meade base waving Free Bradley placards and flags. “It’s been a brutal trial. It’s clear they want to lock him up for life and keep him away from the public for ever,” said Yoni Miller, 19, of New York, who was also wearing a T-shirt bearing the image of Snowden. “Ultimately they are covering up the war crimes that have been exposed by Bradley Manning.”

Chuck Heyn, 66, a Vietnam War veteran, has repeatedly driven from Pennsylvania to try to get a seat in the court martial. “I have been in his shoes,” he said. “I know how tough it is to come forward with information if you find it. The truth hurts. But when you know the truth you have to do something about it. My goal is to continue keeping his goal alive - to get the truth out there, to bring about change in this country and instigate accountability.”

Profile: The boy who went from Wales to WikiLeaks

Bradley Manning was born in 1987 and brought up in Crescent, a small town in rural Oklahoma. His American father, Brian, had spent five years as an intelligence analyst in the US military.

Manning reportedly created his first website aged 10, and took the top prize at a local science fair for three years running. His parents divorced in 2001, and he moved with his Welsh mother, Susan Fox, to Haverfordwest in Pembrokeshire.

Small for his age – even as an adult, he is still little more than 5ft – he suffered bullying in Wales, and is said to have been taunted for being gay and geeky.

With his mother increasingly unwell, he returned to the US without her in 2005, when he was 17, and after two years in a series low-paid jobs, finally enlisted in the army to help fund a college degree.

Allegedly bullied again during military training, and almost discharged altogether, in 2009 Manning was nonetheless posted to Iraq as an intelligence analyst. Reports suggested he sank into a depression following a relationship break-up.

A private first class, Manning had a minimal wage and rank but his work at US Forward Operating Base Hammer, near Baghdad, gave him access to vast amounts of sensitive information. As he delved through the files he became increasingly disillusioned with US foreign policy. He would later leak what he saw to WikiLeaks.

Tim Walker

Timeline: History of a whistleblower

October 2009 Bradley Manning is posted to Iraq as an intelligence officer.

November 2009 Manning contacts the WikiLeaks founder Julian Assange for the first time.

February-April 2010 Manning allegedly sends footage of a US air strike in Iraq – during which American helicopters fired on and killed civilians in Baghdad – to WikiLeaks, which posts it on the internet as “Collateral murder” on 5 April.

May 2010 First contact between Manning and the ex-hacker Adrian Lamo takes place. Manning ultimately confesses having sent the documents to WikiLeaks. Lamo contacts the authorities.

May 2010 Manning is arrested and placed in pre-trial confinement at Camp Arifjan in Kuwait.

July 2010 Manning is charged with leaking the video and secret diplomatic cables to WikiLeaks.

March 2011 Twenty-two new charges are brought against Manning, including “aiding the enemy” (punishable by death). He accuses Virginia brig jailers of “unlawful pre-trial punishment” including stripping him naked every night.

April 2011 Manning is moved to a Kansas jail after international criticism over his treatment in Virginia.

February 2012 A military investigator determines that Manning will stand trial. Months of pre-trial hearings ensue.

March 2012 The UN special rapporteur releases report accusing US government of inhumane treatment of Manning.

February 2013 Manning pleads guilty to 10 of the 22 charges against him but denies the most serious charge of aiding the enemy.